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High-Efficiency, 10-Pin µMAX, Step-Down Controllers for Notebooks

Product Details

Key Features

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 5
VIN (V) (max) 20
VOUT1 (V) (min) 0.5
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 2
Switch Type External
Preset VOUT (V) 5
Output Adjust. Method Preset
Resistor
Synchronous Switching? Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 300
Package/Pins UMAX/10
Budgetary
Price (See Notes)
3.59
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Simplified Block Diagram

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Parameters

Key Features

  • High Operating Frequency (300kHz)
  • No Current-Sense Resistor
  • Accurate Current Limit
  • ±1% Total DC Error over Line and During Continuous Conduction
  • Dual Mode Fixed Output
    • 1.8V/2.5V/adj (MAX1762)
    • 3.3V/5.0V/adj (MAX1791)
  • 0.5V to 5.5V Output Adjust Range
  • 5V to 20V Input Range
  • Automatic Light-Load Pulse Skipping Operation
  • Free-Running On-Demand PWM
  • Foldback Mode™ UVLO
  • PFET/NFET Synchronous Buck
  • 4.65V at 25mA Linear Regulator Output
  • 5µA Shutdown Supply Current
  • 230µA Quiescent Supply Current
  • 10-Pin µMAX Package

Applications/Uses

  • 2-Way Pagers
  • Analog Cellular Phones
  • Digital Cellular Phones
  • Digital Still Cameras
  • Notebook Computers

Description

The MAX1762/MAX1791 PWM step-down controllers provide high efficiency, excellent transient response, and high DC output accuracy needed for stepping down, high-voltage batteries to generate low-voltage CPU core, I/O, and chipset RAM supplies in notebook computers and PDAs.

Maxim's proprietary Quick-PWM™ pulse-width modulator is a free-running constant on-time type with input feed-forward. Its high operating frequency (300kHz) allows small external components to be utilized in PC board area-critical applications such as subnotebook computers and smart phones. PWM operation occurs at heavy loads, and automatic switchover to pulse-skipping operation occurs at lighter loads. The external high-side p-channel and low-side n-channel MOSFETs require no bootstrap components. The MAX1762/MAX1791 are simple, easy to compensate, and do not have the noise sensitivity of conventional fixed-frequency current-mode PWMs.

These devices achieve high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by their ability to drive synchronous-rectifier MOSFETs. The MAX1762/MAX1791 come in a 10-pin µMAX® package and offer two fixed voltages (Dual Mode™) for each device, 1.8V/2.5V/adj (MAX1762) and 3.3V/5.0V/adj (MAX1791).

Simplified Block Diagram

MAX1762, MAX1791: Typical Operating Circuit MAX1762, MAX1791: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .